The invention relates broadly to an exercise machine and, more particularly, pertains to an improved and simplified motion translation arrangement which maximizes the muscular benefits of an exercise motion while minimizing stress to the joints and skeletal structure associated with the muscle group being exercised.
As is well known, many types of exercise machines have been designed to develop or rehabilitate specific muscle groups of the human body. Most of these machines have one or more operating levers or other instruments to be engaged by one while performing desired exercises. The operating levers are generally disposed in the machine to follow a prescribed exercise path. The exerciser is therefore induced to move his or her body according to the particular structure of the machine.
Machines of this variety offer a certain amount of exercise control in direct contrast to the use of free weights still preferred by many exercisers. Exercise movements with free weights are not constrained to follow predetermined planes of motion or prescribed angles. On the other hand, besides being generally safer then free weights, exercise machines address the various xe2x80x9csticking pointsxe2x80x9d experienced in motions with free weights and have attempted to match a resistance variation throughout an entire range of motion with the natural strength curve of a particular muscle group. Although this controlled movement is generally desirable in order to isolate or associate an exercise with particular muscles or muscle groups, the mechanical design of the prior art exercise machines often defines a motion which is incompatible with the musculoskeletal makeup of the body.
This is particularly true in exercising muscles of the upper torso which commonly involve the shoulder, wrist and elbow joints. Because the shoulder joint, in particular, is subject to flexion, extension, abduction, adduction, rotation and combinations of these movements, it is extremely important that the use of the exercise machine will not cause the shoulder joint to be subjected to unnatural movements over the range of movement of the joint.
U.S. Pat. No. 5,810,701 issued to Ellis et al. on Sep. 22, 1998 and assigned to the assignee of the current application specifically addresses the shortcomings of the prior art discussed above. In the Ellis et al. patent, there is disclosed a motion translation arrangement in a shoulder press machine having a seat, a backrest and fixed framework at the top of which a carriage is mounted. The carriage has a pair of downwardly and forwardly extending, diverging lever arms which are tied together and moved upwardly and downwardly along a major horizontal axis mounted to the framework behind the backrest and a minor horizontal axis offset behind and parallel to the major horizontal axis. As the lever arms are moved together upwardly, they are simultaneously swung inwardly about a pair of parallel, angular pivot axes, the swinging motion being transferred via a pair of transfer linkages to pivot the pair of sleeves about the minor horizontal axis. As a result of these linkages, a shoulder press machine is provided in which an exerciser""s hands rotate or supinate naturally through approximately 20 degrees to 30 degrees as the lever arms are pushed upwardly progressively through converging, convex arcs. The inventive machine much more easily accommodates the natural musculoskeletal makeup of the human body without stress to the shoulder joints.
While the Ellis et al. machine performs generally satisfactorily in most cases, it has been discovered that the machine does not always provide a full range of motion, particularly for users with long arm lengths. That is, a user with long arm lengths can be prevented from full extension of his/her arms because of the meeting of the lever arms as the lever arms travel through their progressively converging, convex arcs and approach their uppermost position. Accordingly, it would be desirable to modify the Ellis et al. motion translation arrangement so as to improve the range of motion of the exercise for users regardless of their arm lengths while still maintaining a natural motion compatible with the musculoskeletal makeup of the body. It is also desirable to provide an exercise machine utilizing lever arms with handles moveable through limited converging, concave arcs in such a manner that the rate of convergence of the lever arms decreases and reaches substantially no convergence as the lever arms are raised towards an uppermost position.
It is one object of the present invention to provide an improved method and apparatus for the exercise of an upper torso of a person.
It is a further object of the present invention to provide a carriage arrangement for defining an exercise path which will enable full resistance over an entire range of exercise motion with a minimum of stress on the shoulder, elbow and wrist joints.
It is an additional object of the present invention to provide an exercise machine which particularly accommodates, users with long as well as short arm lengths.
It is also an object of the present invention to provide a shoulder press machine which effectively and safely exercises the deltoids, pectoral muscles and triceps.
Still another object of the present invention is to provide a low lat pull machine employing a motion translation arrangement as applied to the shoulder press machine.
Yet another object of the present invention is to provide an exercise machine which offers a degree of supination or pronation.
In one aspect of the invention, a shoulder press machine having a variable resistance provided therein includes a frame and a seat mounted to the frame. A motion translation arrangement is pivotally mounted to the frame about at least one horizontal axis and defines a first pair of spaced, parallel pivot axes lying perpendicular to the horizontal pivot axis. A pair of lever arms is movable against the variable resistance, the lever arms having rearward portions pivotally connected to the carriage about the first pair of pivot axes, rearward ends rotatably mounted about a second pair of pivot axes lying perpendicular to and below the horizontal pivot axis, and downwardly extending, outwardly diverging forward ends having inwardly extending handles. The motion translation arrangement is constructed and arranged to provide a shoulder exercise motion for an exerciser occupied in the seat wherein the handles and lever arms are moved in curved, converging planes from a lowermost location to an uppermost location substantially upwardly, rearwardly and inwardly from the lowermost location. The lever arms are moved in such a way that the rate of convergence decreases as the lever arms are raised to a point of substantially no convergence so as to provide an optimum range of motion for users regardless of their arm length. The variable resistance is preferably a weight plate removably connected to each of the lever arms. The second pair of pivot axes are defined by a pair of machine frame knuckles fixedly connected to a back of the frame. The second pair of pivot axes are located below the rearward ends of the lever arms.
In another aspect of the invention, an exercise machine has a frame and a seat adjustably mounted on the frame. A carriage is pivotally mounted to the frame about a horizontal pivot axis, the carriage defining a first pair of spaced, parallel pivot axes lying perpendicular to the horizontal pivot axis. A pair of curvilinear lever arms is provided, each having one rearward portion pivotally connected to the carriage at one of the first pair of pivot axes, a rearward end rotatably mounted about one of a second pair of pivot axes lying below the horizontal pivot axis and a forward end provided with a handle. Structure is provided for resisting movement of the lever arms. With this construction, movement of the lever arms and the carriage against the resisting structure and about the horizontal pivot axis will be translated into lateral motion of the lever arms about the first and second pair of pivot axes such that each of the handles will move in converging, concave arcs from a first location spaced laterally from a vertical plane bisecting the exercise machine to a second location substantially upwardly, rearwardly and inwardly from the first location, the lever arms being moved in such a, way that the rate of convergence decreases as the lever arms are raised to a point of substantially no convergence so as to provide an optimal range of motion for exercisers regardless of their arm length. The seat is adapted to support an exerciser in a declined seated position straddling the vertical plane. Each of the lever arms is provided with at least one laterally extending spindle for supporting at least one weight plate. An initial starting position for each lever arm is about 20xc2x0 from horizontal. The rearward end of each lever arm includes an arm knuckle moveably joined by a connector link to a frame knuckle mounted at a back end of the frame.
In yet another aspect of the invention, an exercise machine has a frame, a seat mounted on the frame and a pair of lever arms pivotally mounted relative to the frame and having handles mounted thereon. The invention is improved by a carriage pivotally mounted to the frame about a horizontal pivot axis. The carriage defines a first pair of parallel, spaced pivot axes lying perpendicular to the horizontal pivot axis and has a pair of transfer linkages. Each linkage is swingably connected at one end to one of the lever arms and pivotally connected at another end to the frame about a second pair of pivot axes located below the horizontal pivot axis. Movement of the lever arms and the carriage about the horizontal pivot axis and the first pair of pivot axes will be translated into lateral motion of the lever arms about the second pair of pivot axes such that each lever arm moves in a concave path from a first location to a second location in such a manner that the handles are prevented from contacting each other as the lever arms approach the second location. The exercise machine may be in the form of a shoulder press machine or a low lat pull machine. Each transfer linkage is comprised of an arm knuckle attached to a rearward end of one of the lever arms, a frame knuckle joined to a back end of the frame and a connector link joining the arm knuckle and the frame knuckle. The horizontal pivot axis passes through a shaft rotatably supported in a set of primary pillow block bearings mounted on the frame. Each of the first pair of pivot axes passes through a shaft rotatably supported in a set of secondary pillow block bearings mounted on the carriage.